The laboratory continues to work on newly identified strains of mycoplasma originated from AIDS patients. One of the isolates: Mycoplasma incognitus was found to be infectious in cell culture and in monkey to cause waste syndrome and death. Specific genetic clones and antibodies were obtained for this agent and were used to probe infected tissues. Attempts have been made to develop molecular and serological assays for the agent and specific immunoresponse to this agent. These assays were used to assess the significance of infectivity and pathogenicity of this agent in humans. Genetic analysis of this agent by liquid hybridization procedure has shown that DNA of this agent closely resembles M. fermentant. M. fermentant has been associated with leukemia previously. Coinfection with M. incognitus enhances the ability of HIV-1 to induce cytopathic effects on human T lymphocytes in vitro. Another agent, Mycoplasma penetrans, is a new species of mycoplasma isolated from the urogenital tract of patients with AIDS. This organism has properties of adherence, hemadsorption, cytadsorption and invades many different types of mammalian cells. Detailed serological and molecular biological studies have just begun.